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R.'G-. MARX AND L. F. FULLER.

RADIOTELEGRAPHY.

APPLICATION FILED AUG-13.1917.

1,316,172, Patented Sept. 16, 1919.

' H. 6. M/i/PX Wet/Yeas L. E FULL/5F? ATTORNEYS i r G. MARX, OF PALO ALTO, AN 1) LEONARD F. FULLER, OF SAN OISCO,

CALIFORNIA, ASSIGNORS T'O FEDERAL TELEGRAPH COMPANY, OF SAN FRAN- CISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

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Specification of Letters Patent. I

Patented Sept. 16, 1919.

Application filed August 13, 1917. Serial No. 185,908.

.and LEONARD F. FULLER, citizens of the United States, and residents, respectively, of Palo Alto, Santa-Clara county,'and the city and county of San Francisco, both lIi the State of California, have invented cer tain new and useful Improvements in Radio telegraphy, of which the following is a specification.

The invention relates to a means of signaling and particularly to means of signaling with are radio. transmitters.

An object of the invention is to provide means for signaling which requires the handling of only relatively small currents.

Another object of the invention is 'topro vide means for signaling involving extinguishing and re-igniting the are. The invention possesses, other advanta geous features, somelof which, with the foregoing, will be setforth at length in the following description, where we'shall outline in full that form of the invention which we have selected for-"illustration in the drawings accompanying and forming part of the present specification. It is to be understood,

of one form of the system of our invention.

b ll

Fig. 2 is adiagrammatic representation of a modified form.

Fig 3 is a diagrammatic representation of the potential curve across the are. t

The potential curve 2 taken across the arc is a very irregular curve having sharp peaks 3 without which the arc cannot oscillate" and we provide meansfor robbing the potential curve of its peaks. robbed of its peaks; the arc is extinguished and radiant energy is not emitted from the antenna circuit. Signaling is accomplished by altern telyextinguishing and-reigniting the'arc a telegraphic speed. i

The transmission system comprises an arc oscillation generator 4, which is grounded on one side, preferably the negative, and

. connected on the other side to the antenna 5 through the variable inductance orloading When the curve is so coil 6.- Direct current is supplied to the arc oscillation generator by the generator ,7 and a choke coil 8 is arranged in the lead 9 connected to the antenna side of the arc. The are is subjected to a strong transverse magnetic field produced by the magnet coil 12, which may be separately excited by the generator l3.

{The potential wave produced by the arc has a very jagged form, developing sharp peaks; and-the wave may be robbed of these peaks at the are or in theloading coil. This Jagged wave form is impressed upon the first few turns of the antenna loading coil 6. In Fig. 1 we have shown the means for robbing the wave form of its peaks connected across the lower turns of the loading coil and in Fig. 21 we have shown this means connected across the arc.

Connected across the lower turns of the loading coil (Fig. 1).is a circuit containing an electrolytic lightning arrester 14 which acts as a potential valve and a signaling key 15. The lighting arrester is made up of two or more aluminum cells, connected in series, each cell consisting of two aluminum plates on which has been formed by chemical or electro-chemical pro pesses, a film of hydroxid of alumi'niim, the plates being immersed in 21! suitable electrolyte. .When the jagged wave form is impressed on the arrester, the film opens, as it were, and a current limited only by the internal resistance of the cells, which is low, fidws through the 'arresterl The part of the potential curve eliminated by the cells is indicated by the shaded portions '16 of the potential curve. When the signaling key 15 is closed,

the wave form is robbed of its potential are is shown herein, thismeans being so arranged that the arc 1s ignited as the lightning arrester circuit is opened. Connected acrossv the arc is a spark circuit containing the spark gap 17, the secondary of the trans former 18 and the capacity 19 shunting the secondary. A stopping resistance 21 is arranged between the spark gap and the antenna side of the arc to prevent direct current sufficient to maintain an arc across the spark gap from following the radio frequency current across the spark gap and passing through the secondary. The primary of the transformer is-in series with an alternating current generator 22 and a switch 23 in the primary circuit is attached to the key 15 by an insulating rod 24. When the lightning arrester circuit is opened, the circuit through the primary is closed, producing a high potential in the spark circuit and producing a spark across the spark gap which sets up radio frequency surges which ignite the arc.

We claim:

1. An are system for radio signaling comprising an are, a current supply and an antenna circuit connected to the arc, and a circuit containing an aluminum lightning arrester arranged to shunt a portion of the oscillations produced by said are.

2. An are system for radio signaling, com prising a current supply and an oscillation circuit connected to an arc and a circuit containing a potential valve arranged to shunt a port1on of the oscillation circuit.

3. An are system for radio signalin comprisinga current supply and an osci ation circuit connected to an arc and a circuit containing a potential valve and a signaling key arranged in shunt on a portion of the 0scillation circuit. Y

4. An are system for radio signaling comprising a current supply and an osci lation circuit connected to an arc and a circuit" containing an aluminum lightnin arrester.

. and a signaling key arranged in s unt on a portion of the oscillation circuit.

5. An are system for radio signahn comprising an are which produces an osc1 lating current having a peaked potential wave form, means for robbing the wave of its peaks whereby the arc is extinguished and means for reigniting the are.

6. An are system for radio signaling comprising a current supply and an oscillation circuit connected to an arc, a circuit containing a potential valve adapted to be shunted across a portion of the oscillation circuit, whereby the are is extinguished, and means for reigniting the arc.

7. An are system for radio signaling comprising a current supply and an oscillation circuit connected to an arc, a circuit con taining a potential valve and a signaling key shunting a portion of the oscillation circuit, the closing of said key serving to extinguish the arc, and means operative in time with the opening of said key for reigniting the are.

8. An are system for radio signaling comprising a current supply and an oscillation circuit connected to an are, a circuit containing an aluminum lightning arrester, and a signaling key shunting a portion of the oscillation circuit, the closing of said key serving to extinguish the arc, and means operative in time with the opening of said key for reignitin the are.

9. The method of producing radio signals with an are which produces an oscillatory current having a peaked otential wave form, which consists in rob ing the wave of its peaks.

10. The method of producing radio signals which consists in producing an oscillatory current havin a peaked potential wave form in an osci ating circuit and intermittently removing the peaks by shunting the circuit.

In testimon whereof, I have hereunto set my hand at onolulu, Territory of Hawaii, this 19th dayof July 1917.

Ron/1ND G. MARX.

In testimony whereof, I have hereunto set my hand at the city and county of San Francisco, State of California, this 31st day of July, 1917.

LEONARD F. FULLER. 

